/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.iotdb.db.metadata.mtree.traverser.collector;

import org.apache.iotdb.commons.exception.MetadataException;
import org.apache.iotdb.commons.path.PartialPath;
import org.apache.iotdb.db.metadata.mnode.IMNode;
import org.apache.iotdb.db.metadata.mtree.store.IMTreeStore;
import org.apache.iotdb.db.metadata.mtree.traverser.Traverser;

// This class defines the generic resultSet as traversal result and add more restrictions on MTree
// traversal.
public abstract class CollectorTraverser<T> extends Traverser {

    // used for implement slimit and offset function in DDL
    protected int limit;
    protected int offset;

    protected boolean hasLimit = false;
    protected int count = 0;
    protected int curOffset = -1;

    protected T resultSet;

    public CollectorTraverser(IMNode startNode, PartialPath path, IMTreeStore store)
            throws MetadataException {
        super(startNode, path, store);
    }

    public CollectorTraverser(
            IMNode startNode, PartialPath path, IMTreeStore store, int limit, int offset)
            throws MetadataException {
        super(startNode, path, store);
        this.limit = limit;
        this.offset = offset;
        if (limit > 0 || offset > 0) {
            hasLimit = true;
        }
    }

    /**
     * extends traversal with limit restriction
     */
    @Override
    protected void traverse(IMNode node, int idx, int level) throws MetadataException {
        if (hasLimit && count == limit) {
            return;
        }
        super.traverse(node, idx, level);
    }

    /**
     * After invoke traverse(), this method could be invoked to get result
     *
     * @return the traversal result
     */
    public T getResult() {
        return resultSet;
    }

    public void setResultSet(T resultSet) {
        this.resultSet = resultSet;
    }

    public int getCurOffset() {
        return curOffset;
    }

    public void setLimit(int limit) {
        this.limit = limit;
        if (limit > 0) {
            hasLimit = true;
        }
    }

    public void setOffset(int offset) {
        this.offset = offset;
        if (offset > 0) {
            hasLimit = true;
        }
    }
}
